Search results for "performance"
showing 10 items of 4457 documents
Ultra-Wideband Radio Signals Distribution in FTTH Networks
2008
[EN] The use of an ultra-wideband (UWB) radio technique is proposed as a viable solution for the distribution of high-definition audio/video content in fiber-to-the-home (FTTH) networks. The approach suitability is demonstrated by the transmission of standards-based UWB signals at 1.25 Gb/s along different FTTH fiber links with 25 km up to 60 kin of standard single-mode fiber length in a laboratory experiment. Experimental results suggest that orthogonal frequency-division-multiplexed UWB signals exhibit better transmission performance in FFTH networks than impulse radio UWB signals.
Experimental characterization of PEM fuel cells by micro-models for the prediction of on-site performance
2009
This paper presents the results of an experimental analysis performed on a miniaturized, 6 We Proton Exchange Membrane Fuel Cell (PEMFC) system, integrated with on-site hydrogen production by electrolysis; in particular, the effects of environmental parameters such as the external temperature and the humidity on the performance of fuel cells are investigated. PEMFC systems are zero-emissions power technologies when they are fed with pure hydrogen (at concentration higher than 97%); also, being the only results of system operation the produced electricity and some pure water, when produced by renewable sources hydrogen can be considered an attractive alternative to fossil fuels and may concu…
The Performance Evaluation of Polytechnic Higher Education Institutions: Tensions and Reconfigurations Resulting from the Adoption of Specific Metrics
2017
Aligned with the binary structure of the higher education system in Portugal, divided into universities and polytechnics, the Government acknowledged, in 2014, the need to identify distinct performance indicators/metrics aiming at a more accurate assessment of the effect and quality of the action developed by Higher Education Institutions (HEIs). For the Polytechnic Higher Education Institutions (PHEIs) it was necessary to define «(...) performance indicators that address the production, transfer and diffusion of knowledge» (FCT, 2014: 1), aiming to measure «(...) the applied research and the cultural production activities as well as their impact on the region where they [PHEIs] are located…
Reverse electrodialysis
2016
Abstract Reverse electrodialysis (RED) technology has grown significantly in the last decade, gaining a fast increase in its technology readiness level and presenting some interesting examples of RED pilot systems operating under very different real environments. In this chapter, an overview of technological developments and piloting examples are reported. In particular, a short introduction is given on the historical trend of RED technology growth, followed by a careful analysis of which feed solutions can be adopted and how these can affect the process performance, potentials, and applications. Most prominent fluid dynamics aspects for the RED process are presented, highlighting how these…
Evaluation to support stakeholder centered design and continuous quality improvement in higher education services
2014
Abstract: Evaluation and self-evaluation procedures are commonly used in educational institutions to measure education services and research performance. This chapter describes the main opportunities that evaluation-based approaches can produce to support processes of design and continuous quality improvement in higher education institutions in the light of recent normative measures in Italy to address quality aspects of education services. Subsequently, a new approach – based on the ServQual conceptual model – that evaluates education services is used to carry out a strategic analysis of education services at the management engineering program at the University of Palermo, Italy.
Towards more equity concerning quality of Urban Waste Management services in the context of cities
2018
Abstract An innovative combined evaluation approach is proposed in the present paper to deal with the issue of the performance measurement and comparison of Urban Waste Management (UWM) services in the context of cities. The ELECTRE III method is initially considered as tool able to execute a multi-criteria analysis aimed at ranking UWM systems based on their integration and sustainability levels. The latter are comprehensively evaluated via the recently developed “Wasteaware” Integrated and Sustainability Waste Management indicators framework, which takes into account physical components and governance aspects of UWM systems. Then, on the basis on ELECTRE III results, a practical gaps inve…
Annual heating energy requirements of office buildings in a European climate
2016
Abstract The concept of implementing energy savings to reduce greenhouse gas emissions has become a key element of energy policies of any industrialized country. In the civil sector and specifically, energy savings for office buildings, there are still opportunities for further enhancements related to correctly determining the air conditioning thermal requirements. However, there is a lack of simple correlations that allow a preliminary assessment for a single building or correlations that can be quickly applied at the district level. This paper proposes several simple correlations that determine the heating loads of a typical office building by only knowing the Degree-Days of a specific Eu…
Comparing different control strategies for indoor thermal comfort aimed at the evaluation of the energy cost of quality of building
2010
Abstract The rapid improvement in the standard of living requires more detailed and sophisticated methods of evaluating comfort conditions. But, maintaining thermal comfort conditions in confined environments may require complex regulation procedures and the proper management of heating, ventilating and air conditioning (HVAC) systems. In turn, the requirements for indoor thermal comfort do not necessarily coincide with those of energy saving purposes, which in the last years are becoming a crucial issue owing to the enactment of the European Energy Performance of Buildings Directive (EPBD). The aim of this work is to compare different indoor control thermal comfort strategies in view of th…
Coupling CFD with a one-dimensional model to predict the performance of reverse electrodialysis stacks
2017
Abstract Different computer-based simulation models, able to predict the performance of Reverse ElectroDialysis (RED) systems, are currently used to investigate the potentials of alternative designs, to orient experimental activities and to design/optimize prototypes. The simulation approach described here combines a one-dimensional modelling of a RED stack with a fully three-dimensional finite volume modelling of the electrolyte channels, either planar or equipped with different spacers or profiled membranes. An advanced three-dimensional code was used to provide correlations for the friction coefficient (based on 3-D solutions of the continuity and Navier-Stokes equations) and the Sherwoo…
PV systems in the vertical walls: A comparison of innovative structures
2016
This paper presents the performance comparison of PV windows with the purpose of tracing the behavior of next-generation systems, which could favor architectonical integration. More in detail, a dye sensitized solar cell (DSSC) and blue and grey thin film silicon panels have been analyzed. The systems can be placed behind a window or behind a wall of glass blocks. The three generation systems are then compared in terms of both efficiency and Fill Factor.